104 duodenal ulcer patients were classified into non-smokers (76) and smokers (28). Their age range was between 14-72 years. They were randomly treated with cimetidine (28 non-smokers and 8 smokers), colloidal bismuth (27 non-smokers and 10 smokers) and sucralfate (21 non-smokers and 10 smokers). Follow-up endoscopic examination at 4, 6 and 8 weeks showed that overall healing rates were better in the non-smokers than in the smokers (64.5% against 46.4% at 4 weeks and 92.1% against 67.8% at 6 weeks) and almost all ulcers had healed at the end of 8 weeks (100% in non-smokers and 96.4% in smokers). Among non-smokers, there were no statistically significant differences in the healing rates by any medication at any period of time. Among smokers, colloidal bismuth had significant better healing rate at 6 weeks over cimetidine and sucralfate. (p = 0.04 and p = 0.041 respectively). Overall relapse rates were higher among smokers (32.1%) than non-smokers (10.5%). Of the 3 medications, sucralfate had the lowest relapse rate in both smokers (20%) and non-smokers (9.5%), while colloidal bismuth had the highest relapse rates (40% for smokers and 11.1% for non-smokers).